132 MASS. EXPERIMENT STATION BULLETIN 254 



From the leaf counts made on October 25, early blight was rather more promi- 

 nent on the sprayed plots and late blight on the check. The celery from the treated 

 plots was excellent with a neghgible percentage of infection. That from the check 

 plots showed considerable early and late blights, confined largely to the outer 

 J eaves, which did not materially affect its value. The basic sulfate without 

 spreader was fully as effective as with the combined spreader or as Bordeaux. 

 Saponin increased wetting and spreading, but Wilkinite proved of no particular 

 value unless possibly to increase visibility (Guba). 



Potatoes 

 Experiments were conducted on the farm of E. S. Fulton at North Amherst 

 under the supervision of W. L. Doran of the department of botany of this Station 

 to determine the relative effectiveness of basic copper sulfate and of Bordeaux in 

 controlling early and late bUghts on potatoes. Uncertified Green Mountain seed 

 was used without disinfecting. The fungicides were basic copper sulfate (lot 3) 

 4-50 with combined spreader and homemade Bordeaux 4-4-50, to which was 

 added lead arsenate when necessary for the control of the Colorado potato 

 beetle. Applications were made on July 15 and 26 and August 9 and 18 with a 

 Yellow Jacket equipment under a pressure of 175 pounds, 2 nozzles to a row, and 

 about 90 gallons to the acre. Leaf hopper or tipburn injury, leaf-roll and late 

 bUght were the principal infestations of the season. Leaf hoppers were very 

 prevalent and no nicotine sulfate was employed. Early blight was inappreciable; 

 late blight was late in appearing and probably did not constitute a serious factor. 

 On harvesting there was not over 1 or 2 per cent of tuber rot. The yield was 

 calculated from the weight of the two inside rows (equivalent to J^ acre) in each 

 plot on the basis of marketable potatoes, 60 pounds to the bushel. 



Table 4. Relative Effectiveness of Basic Copper Sulfate and Bordeaux in Controlling: 

 Early and Late Blights of Potatoes— As Shown by Yields 



Number Number 



Copper of of Yield Gain or loss over 



Fungicide content appli- rows per cheek 



cations treated acre 



Per cent Bit. Bu. Per cent 

 Basic copper sulfate 4-50 



East plot 0.25 4 8 190.4 —6.4 —3.25 



West plot 0.25 4 8 189.6 —7.2 —3.66 



Average 190.0 — 6.8 — 3.46 



Bordeaux mixture 4-4-50 



East plot 0.26 4 8 192.0 —4.8 —2.U 



West plot 0.26 4 8 217.6 -f20.8 +10.57 



Average 204.8 -(-8.0 -|-4.07 



Check 0.00 4 196.8 



Observations and yields indicate that basic sulfate was rather less efficient in 

 controlling late blight than Bordeaux, although only one of the sprayed plots 

 showed an increase in yield over the check. Furthermore, the number of applica- 

 tions would have been decidedly inadequate in so rainy a season had bhghts 

 appeared earlier. 



Fruits. 



Experiments were conducted in the College orchard and vineyard under the 

 supervision of J. K. Shaw and O. C. Roberts to determine disease control and 

 foUage injury of basic sulfate on Baldwin and Mcintosh apples, Monarch plums 

 and Moore's early grapes. The highest concentration employed was 4 pounds 

 to 50 gallons with combined spreader. Concentrations of 3 and 2 pounds were 



